What goes wrong

The wrong side of a threshold

Updated October 2026

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The three numbers Seasonal blends move A cheaper carrier changes the hydrocarbon count Nothing in the supply chain reports it And a premix is not exempt because it is dilute Write the computed figure down, not the conclusion Recompute on every change Who owns the recomputation References

Three different numbers govern this group, and a product can cross one without anything visible changing.

The three numbers

Methanol at 4 percent, ethylene glycol at 10 percent, hydrocarbons at 10 percent under 100 SUS. Each is a percentage by weight and each one, crossed, brings tested child-resistant packaging with it.

Seasonal blends move

A washer fluid rated to a colder temperature carries more methanol. If one blend in a range sits above 4 percent and another below, they are two different packaging problems in identical bottles, which is a labeling and stock-control trap.

A cheaper carrier changes the hydrocarbon count

Substituting a solvent for cost is a purchasing decision that can move a regulatory line, and the purchasing decision rarely reaches whoever owns the label. That is an organizational failure more than a technical one.

Nothing in the supply chain reports it

Bottles, closures and labels all arrive the same whatever the formula says. The only place a crossing is detectable is your own formula sheet, recomputed.

And a premix is not exempt because it is dilute

A 50/50 coolant is still far above 10 percent glycol. Dilution helps only where it actually lands below a threshold, and believing it helps in general is how this goes wrong.

Write the computed figure down, not the conclusion

The percentage, the date and the formula version. A conclusion with no working cannot be rechecked after a reformulation, so in practice it gets taken on trust until something forces the question.

Recompute on every change

New supplier, new carrier, new dilution, new temperature rating. It is arithmetic on a sheet you already have, and it takes minutes against a production run.

Who owns the recomputation

In a small operation it is whoever changed the formula; in a larger one it is nobody, because purchasing, blending and labeling sit apart. Naming the owner is a cheaper control than any test, and it is the one that actually catches a carrier substitution.

References

16 CFR 1700.14, Substances requiring special packaging. Paragraph (a)(8) covers methanol at 4 percent or more by weight; (a)(11) ethylene glycol at 10 percent or more; (a)(31) nonemulsion liquid household chemical products at 10 percent or more hydrocarbons by weight under 100 SUS at 100 F. law.cornell.edu

16 CFR 1500.14, Products requiring special labeling. Paragraph (b)(2) requires "warning" and "Harmful or fatal if swallowed" for 10 percent or more ethylene glycol; (b)(3)(ii) requires "danger", "Harmful or fatal if swallowed" and "Call physician immediately" for 10 percent or more petroleum distillates, because they may be aspirated into the lungs. law.cornell.edu

Written from federal regulation and from measured catalog data, not from a blending bench. We sell containers and closures; whether a particular closure satisfies a particular clause is a question about that closure and its supplier’s testing, and nothing here certifies a package as compliant. Anything on these pages is a starting point.